gps gprs gsm mobile asset tracking

8/3/2019 Gps Gprs Gsm Mobile Asset Tracking

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GPS/GPRS/GSM based Mobile Asset TrackingOverview

Global Positioning Satellites (GPS) enable the tracking of all kinds of mobile assets accurately and provide their

real time positions to the owners on a 24 by 7 basis over the GPRS/GSM link. While the GPS provides the

latitude/longitude information of the mobile asset a given time, this information can be transmitted to any place

using the GPRS radio link. In fact, the asset can even have enough intelligence built into it to initiate calls usingthe GSM phone links. The technology and the cost of implementing this technology has come down drastically over

the last few years making them very affordable to the general public.

This GPS/GSM/GPRS tracking technology can be used in the following areas, just to name a few:

• Vehicle tracking to accomplish

• Monitoring of speed and location of the mobile asset

• Monitoring of various compliances related to safety, driver behavior, etc.

• Emergency Services: crash reporting, engine stall, etc

• Fleet management;

• Driving pattern, behavior and understanding

• High Value Asset tracking:

o High Value asset/consignment tracking

o This could be International Bulk containers, High Value Containers (airlines, etc), and several

other such assets.

This approach paper is limited to Vehicle tracking only while the same technology could be used with some

modifications in GUI/Software for various other applications as indicated above.

Vehicle and Fleet Management services will consist of a tracking / recording device (Asset Track), which will be

installed in the vehicle that is to be tracked. This will then transmit data about speed, position (through GPS),

forces etc through the GPRS network to a gateway server at a constant predetermined rate. During emergencies,

as pre-defined, the Asset Track device could intimate the date transmission to the server. Operators at the other

end can also initiate calls to the Mobile Asset since the Asset Track has the capability to conduct two way

communications. These servers could store the data (MS SQL or Oracle DB Cluster) for further reporting and

analysis.

This kind of service should be flexible enough to add additional services which are not envisaged today, but may

become necessary in future. The Asset Track device would therefore get periodic updates from the gateway server

as and when updated firmware/applications are available. The Asset Track device could have onboard storage

ability for a certain amount of data.

The data transmission and recording options could be determined by the various levels of services offered and the

clients to this service could opt for these paid services based on their needs.

This document provides an overview of the various building blocks of the solution and identifies the right

technology approach to be adopted for meeting the requirements. The following sections also define the hardware

and software specifications of various components of the system.

High Level Architecture



There are 24 GPS satellites orbiting the earth at approximately 20,000 km. These satellites were launched and are

owned by the US Department of Defence (DOD). Their orbital positions are organized such that, at any location on

earth (without obstruction), at least five of them are guaranteed to be in the line of sight most of the time. These

satellites broadcast free to air signals, which carry information about their exact positions in the orbit and are

precisely synchronized with the moment of time that the signal is generated. GPS receivers, which are mounted to

vehicles, receive these GPS signals, calculate the time difference of arrival (TDOA) and determine all threedimensions of the vehicle’s current coordinates as well as the precise time. Determination of four parameters

requires signal reception from at least four satellites and hence at least four satellites need to be in the line of

sight. If it so happens that there are only three satellites in the line of sight, position coordinates can still be

detected but the time dimension remains missing. However, because of the purposefully selected orbital positions

at a very high altitude, there always exist enough satellites for a quite precise position determination.

Since the satellites are positioned at a high altitude, a GPS receiver is in contact with at least 5 GPS satellites at

any time. Therefore GPS receivers never fail to detect the location of a vehicle. By using TDOA, the distance

between the calculated and actual locations (the amount of deviation or location error) is 1 to 10 meters with 95%

confidence level. This precision has been achieved and made available to public by an US Government Regulation

dated May 1st 2000.

Raw data sent by the Onboard Vehicle Units are processed in the central computers and turned to a suitable

format. The central Computer System runs the Vehicle Tracking Server Software. By using this software, clients

are able to track their vehicles in real-time on digital maps.

The in vehicle devices calculate speed and location information using GPS signals. GSM networks are used as the

telecommunications infrastructure to transmit this information to the company that owns the vehicle. Software

that controls the whole system and interfaces with the monitoring staff, must be installed in the user company’s

premises. Vehicles under this system can be monitored and managed by the dedicated staff as long as they are in

GSM coverage.

A high level architecture diagram that shows various building blocks of the solution for mobile asset tracking is

given below:



Inside the Vehicle, there needs to be an Asset Track box which would need to interface to the vehicle data port,

typically called On Board Diagnostics port, version II (OBDII). Through this OBDII port, the Asset Track box can

obtain various parameters as indicated below:

• Engine parameters: Speed, Engine Throttle, Brake Status, Gear Selected, Active Handling (traction

control), Drive Train setting, RPM, service due, Odometer, Mass Airflow Sensor (MAF), etc

• Safety parameters: Seat Belt, ABS, Air Bag (multi level) Front/Rear, braking action or lack thereof, Fuel

Tank Level, Seat Occupancy, Error codes, tyre pressure, etc.

• Other: Front/back light status, headlight dip status, indicator status, windscreen wiper status, etc

As can be seen, there are several parameters that can be sampled and based on these samples, decisions aboutvarious attributes of the vehicle can be made to take appropriate and necessary actions such as killing the ignition

to various other activities.

A system level block diagram of the various components for such a monitoring system is given below.



It is a standard N-tier model using a web services based architecture. Asset Track Box is the device installed on the

car. Asset Track Box interfaces with the Car Engine Management System using a CAN Interface through the OBDII

port for getting the speed, forces and related information. It would also interface with the onboard GPS unit to get

the position information. The data is transferred to the Backend DB gateway using HTTP/SOAP or relevant protocol

over a GPRS network.

A network-load-balanced server cluster can be used to implement a high-available and reliable gateway server to

handle the high volume of incoming data. Each of the cluster server can be configured to scale-up by increasing

the in system resources (CPU, memory) and scaled-out by adding more servers to handle future increases in data

volumes, on demand.

The data received by the gateway server cluster is stored, after verification, into a DB Cluster (MS-SQL or Oracle

Database).

A robust Asset Track box hardware and software architecture enables system upgrades to these boxes remotely

(both firmware and system software including applications) and enables the possibility of deploying additional

services above the standard features on this box as they become available or provide a simple upgrade to existing

application services. A device management feature takes care of roll back of the software versions to previous

stable versions in the event of a new upgrade being detected to be not fully operational.

Solution

Various building blocks and our solution approach and technology recommendations are discussed in this section:

Asset Track Box

Asset Track Box is the device that will be installed in the vehicle (independent of Make or Model) and will transmit

data about speed, position, forces etc through the GPRS network to a gateway server by interfacing appropriately

with the OBDII data port of the vehicle. The device will have GPS capability to provide real-time position data.

This device will also receive periodic firmware updates from the server when an update is available. A proposed



hardware and software specification for this device is given below. This is a preliminary specification and might

change based on the final requirements.

Hardware Specifications

CPU/Storage:

ARM core CPU with Star IIe GPS/GPRS chipset 64Mbyte of memory for data storage Optional USB port for fastdownload by direct connect Self diagnostics Self update capability

GPS/GPRS System:

Receiver: L1, C/A code

Snap Start: < 25 minutes off period)

Update rate: 1 HZ

Antenna Type: Built in Patch Antenna

Minimum signal tracked: -175dBW

Power Button: On/off push button

Battery:Lithium-ion battery lasts for more than 9 hours of use, charger

to Car battery

Operation Temperature: -10C to + 60C

Store Temperature: -20C to + 85C

Operation Humidity: 5% to 95% No condensing

Non DGPS (Differential GPS)

Position: 5 - 25 m CEP without SA

Velocity: 0.1m / sec

Time: 1 usec sync GPS time

EGNOS/WAAS

Position:<2.2 m, horizontal 95 % of time

<5 m, vertical 95 % of time

Reacquisition: 0.1 sec. averaged



Hot Start: 8 sec. averaged

Warm Start: 38 sec. averaged

Cold Start: 45 sec. averaged

Interface Specifications:

The type and interfacing specifications of the car engine management is through the OBDII interface, the protocoland other details are well known and can be handled through the system software/firmware. Typically CAN bus

interface is used as the communication protocol, and as such the hardware will be able to handle the bus protocol

requirements.

Typical Hardware Cost:

An Asset Track hardware box with the feature set as described above could cost around $100/box in volumes of

100K/year. The data storage capability is limited to last 30days of data at max with about 1Kbytes of data

generated over each minute (approx about 50Mbytes). There could be additional costs for some of the added

features such as ability to detect crash, fire proof of the box, etc.

Installation of such box in the Vehicle, though a onetime expense could be around $100 per vehicle and could need

activation and additional services to make it available to the user.

Software Specifications:

Software stack on the Asset Track Box can be based on an embedded Operating System like Embedded Linux or XP-

Embedded. Our recommendation is to use embedded Linux, but the choice would depend upon the hardware and

the integration API with the Car Engine Management System. Java or C/C++ can be used if the platform is Linux.

There could be a software frame work which may be required to make some of these features seamless for

integration and upgradability.

Communication FrameworkCommunication between Asset Track Box and the gateway server can be implemented using HTTP/HTTPS/SOAP

protocols over the GPRS network. Data will be sent to the gateway server using HTTP/SOAP protocols. Firmware

and application updates from gateway server to the Asset Track Box will be using proprietary protocols

implemented over standard HTTP/SOAP.

Any communication to the gateway will be authenticated and packets encrypted using SSL/HTTPS.

Data transmission requirements:

Based on the requirement of 1KB of data every 2 minutes, the total amount of data transmission rate for tracking a

million vehicles would be around 60 Mbps, which is very well within the Ethernet standards. Even after adding a

10% overhead for encryption, protocol headers etc, the transmission is still within the 100Mbps/1Gbps Ethernet

standard and can scale easily up for more than 10 million vehicles.

Such services as Short Messaging Services, etc could be made available to the user at additional cost. The data

services from each box could be a subscription service with the telecom operators and could easily cost $30+ per

month for basic services.



Database Gateway

In order to handle the real-time, high-volume data from the network, Gateway Server has to be designed using a

highly scalable architecture. It can be designed as a network-load-balanced cluster of servers scaled out to handle

the high volume of data transmission

Application Scaling:

The two main applications in the Gateway servers are:

Data Receiver Web Service:

This web service would be responsible for handling data from the Asset Track Box devices. When the data is

received, it is verified and is written to a database cluster. This application is not complex by definition and can

be designed as a stateless service so that it can be scaled out to N number of servers to handle the simultaneous

hits. The data can then be passed to the database layer designed using the well-known database scaling solutions.

Simple nature of this web service avoids the need for multiple threads, thereby making it easier to scale up by

adding more resources to the server if needed.

The service can be implemented either using Microsoft .Net or Java Web Services architecture.

Firmware Update Application:

This application service would be responsible for sending firmware or application software updates to the Asset

Track Box devices. When a device checks in to the gateway server, it will also receive notifications on these

updates based on the services subscribed by the box user along with various other parameters. This service can be

designed in such a way that updates do not happen on all the Asset Track Box devices simultaneously. Hashing

algorithms can be developed based on incoming MAC address or device ids so that updates can be distributed over

time. This will avoid processing and network load on the gateway server, also these updates will use the

bandwidth of the telecom operator and thus increasing the cost of ownership.

Load Balancing and Clustering:

Gateway Servers can also be scaled up/out to handle the data volumes by employing the following technologies:

• Network Load Balancing (NLB): provides load balancing support for IP-based applications and services that

require high scalability and availability

• Server Cluster (SC): provides failover support for applications and services that require high availability,

scalability and reliability

Network Load Balancing (NLB) is a clustering technology that distributes TCP requests across servers. For instance,

if there are two servers in a cluster, NLB will allocate TCP requests across those two servers. An NLB can be

configured in the Gateway Server cluster to distribute the network load among the server farm. Number of servers

in the farm can be configured based on the network load.

A Server Cluster takes two or more computers and organizes them to work together to provide higher availability,

reliability, and scalability than can be obtained by using a single system. Data Vault Gateway Cluster can be

configured to redirect and redistribute the workload in the event of failures.

Together, these two technologies combine to insulate the solution from application and service failure (software

crashes), system and hardware failure (disk crashes), and even site failure (natural disasters, power outages,

network interruptions, and so on).



Software Recommendations

Our recommendation is to use Windows Server 2003 as the Gateway Server Platform. Windows Server 2003 is

designed to work in the distributed and highly scalable world like the Data Gateway. Windows Server 2003 also

offers greater support for Storage Area Networks (SANs), which significantly increase the amount of storage

available. Virtual Disk Service (VDS) lets you manage large amounts of storage the same way you manage a local

disk. This impacts scalability because it lets you manage large SANs connected to a server system via fiber.Furthermore, you can use SAN for multiple servers at the same time. Multi-path I/O lets you refer to same disk

using multiple paths, which increases both scalability and availability.

Windows Sever 2003 also supports a Large Send Offload feature that lets the CPU offload major portions of the

TCP/IP stack onto a network card (NIC) that also support this feature.

Gateway applications can be developed using Microsoft .NET as web services over HTTPS/SOAP protocols, with

Microsoft IIS as the application server.

Server Configurations

Two ways of scaling the Data Gateway are to scale up and scale out the hardware configuration:

1. Scaling Out:

Windows Server 2003 supports NLB. This allows you to create an NLB cluster as shown in the following diagram by

simply installing Windows Server 2003 and enabling NLB.

This sever configuration can support up to 32 servers. For instance, you could start the NLB farm with four servers

as shown in the top of the figure, and then add more servers as shown in the bottom part of the figure. NLB is alsoallows you to add or remove servers to a cluster while the cluster is running.

This allows you to expand or contract a farm dynamically as the application needs to scale out. This also allows

you to reconfigure servers in the cluster without taking the entire cluster down.

2. Scaling Up:

Windows Server 2003 provides flexibility by allowing you to scale an application on a single server by adding

resources such as more memory, faster disk, and more and/or faster processors.



Windows Server 2003 can scale from one processor to 32 (Datacenter Edition), resulting in a tremendous amount of

room to grow on a single system. Not only can you scale a single system up, you can also combine the modes.

Combining the two modes provides the most in terms of scalability, reliability, and manageability.

Summary

The initial study of the requirements suggests an embedded Linux platform for the Asset Track Box device,

HTTPS/SOAP over GPRS network as the communication framework and a Windows Server 2003 based NLB Server

Cluster for implementing the Data Gateway.

Since the applications on the Gateway Server are inherently simple in nature, all the scalability and reliability

considerations have to be done while designing the server configurations. Since the scope of hardware design in

this project is unknown, this document does not give any recommendations on the hardware specifications for the

Data Gateway. Instead, only server configuration recommendations are provided.

Typical system costs for such implementation with some of the descriptions of the possible ingredients can be as

follows; of course the volumes will dictate the pricing. These numbers are only indicative for discussion purposes.

• Asset Track box: GPS/GPRS/GSM based with interface to OBDII and has ability to save about 30 days data

at the rate of 1Kbyte per minute of data gathered while in operation. Approx cost $100 for volumes of 100,000

units per year.

• Installation costs: Qualified technicians have to open the hood of the vehicle and install this with

interface to the vehicle battery and OBDII data, expect about $100 per successful installation.

• Commissioning: The Asset Track box has to be registered with the appropriate service provider and

should communicate with the back end server to make it operational. This activation cost could vary between

$30-50.

• Monthly Services: There would be some basic services, limiting the amount of data and reports per

month, which the customer could subscribe to on a monthly basis and this could be as low as $25 per month

and there could be several add on services at additional costs.

Also there could be so many other subscribers to these services such as the Government organization, Insurancecompanies, compliance standards bearers, etc which could be additional sources of revenues.

As the next step, this study has to be validated by understanding the requirements in more detail and also come up

with a validation matrix and a comprehensive proposal for implementing the specific solution as per each customer

requirements.

References

Cal soft Labs has extensive experience in developing the complete GPS/GPRS/GAM system including hardware,

firmware, software, applications and the back end communication gateway to the next generation data centers to

meet the client requirements. Similar systems like Fleet Tracking and Mobile Gateway Communications that

transmits real-time data from mobile devices to a gateway server over GPRS networks have been successfully

implemented already. References to specific case studies can be provided upon request.

gps gprs gsm mobile asset tracking

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